On the Expected Number of Failures and Maintenance Cost Prediction of Repairable Systems From Life Cycle Cost Modeling Perspective

2010 ◽  
Author(s):  
Laxman Yadu Waghmode ◽  
Anil Dattatraya Sahasrabudhe
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Life Time ◽  
Maintenance Cost ◽  
Repairable System ◽  
Repair Cost ◽  
Repairable Systems ◽  
Expected Number ◽  
Maintenance And Repair ◽  
Repair Costs

The objective of this paper is to provide some useful insights on how cost driving events are related to the characteristics of failure distributions and the product lifetime (design life) in case of repairable systems. Repairable systems are those that can be restored to their fully operational capabilities by any method, other than the replacement of the entire system. In case of repairable systems, the components can be repaired or adjusted rather than replaced, whenever a breakdown occurs and thus such systems experience multiple failures over their life span. For majority of repairable systems, the life time maintenance and repair costs dominate the life cycle cost. To predict the maintenance and repair cost, failure data, maintenance data and repair time data is needed which is not readily available at the system design stage. When a repairable system is put into service, how many times it will fail over its life span depends on its reliability. Similarly, how fast the system is restored to its working condition when it fails (maintainability), also affect the costs incurred. Thus, the expected number of failures, time lost in restoring the system after each failure and cost per failure are important from life time maintenance cost prediction viewpoint. The expected number of failures depends upon the time to failure distribution of the system components and the after repair state of the system. In this paper, a modeling methodology is suggested for prediction of life time maintenance and repair cost of repairable systems based on expected number of failures. The repairable system lifetime is modeled using a two parameter Weibull distribution. The expected number of failures are estimated for renewal process (as-good-as-new after repair state) and minimal repair process (as-bad-as-old after repair state). The expected maintenance and repair costs are also evaluated for six different failure distributions. The technique has been illustrated through a specific application, namely an industrial pump and the results are presented.

An Application of a Generalized Life Cycle Cost Model to a Typical Pump From Industry

2009 ◽  
Author(s):  
L. Y. Waghmode ◽  
A. D. Sahasrabudhe
Keyword(s):  
Life Cycle ◽  
Life Span ◽  
Life Cycle Cost ◽  
Cost Model ◽  
Life Time ◽  
Maintenance Cost ◽  
Repairable System ◽  
Repairable Systems ◽  
Generalized Model ◽  
Mean Time

The objective of this paper is to develop a methodology for effective implementation of life cycle costing (LCC) in design and procurement of repairable and non-repairable products. For this purpose, a generalized model for LCC of repairable and non-repairable products has been proposed. The equations of cost components of the proposed generalized model have been formulated for repairable systems based on the reliability and maintainability aspects to enable the life-time cost conscious design of such systems. The repairable systems typically have a life span of 10 to 20 years and experience multiple failures over their life span. The life cycle cost of a repairable system is significantly influenced by its reliability and maintainability. The life time energy and/or maintenance cost often dominate LCC for most of the repairable systems. Under the condition of constant failure rate the repairable system reliability is characterized by mean time between failures (MTBF) and maintainability by mean time to repair (MTTR). A higher value of MTBF and lower value of MTTR results into lower life cycle cost and therefore a due consideration to these factors is essential while designing repairable systems. The generalized LCC model presented in this paper will assist the designers to compare the life cycle cost of their different design alternatives at product design phase wherein most of the life cycle costs are committed. The developed generalized LCC model is applied to a typical repairable system, a pump from industry and the results obtained are presented.

A Comparative Study of Life Cycle Cost Analysis of Pumps

2010 ◽  
Author(s):  
Laxman Yadu Waghmode ◽  
Anil Dattatraya Sahasrabudhe
Keyword(s):  
Life Cycle ◽  
Product Design ◽  
Failure Rate ◽  
Life Cycle Cost ◽  
Global Market ◽  
Design Stage ◽  
Time Interval ◽  
Repair Cost ◽  
Maintenance And Repair ◽  
Initial Cost

For a product to be commercially successful and increasingly competitive in this global market place, it is imperative that engineers must understand and design for each phase in the life cycle of a product. The life cycle cost (LCC) of any piece of equipment, such as a pump represents the total cost to procure, install, operate, maintain and dispose of that equipment. For sustainment dominated products or systems, the lifetime energy and/or maintenance costs dominate the life cycle cost as compared to its initial cost. The initial cost is only a fraction of the life cycle cost. Therefore, a due consideration to the life cycle cost issues at product design stage is quite essential. The LCC analysis is recommended only at the product design phase, as up to 80% of product LCC is committed at this phase. A better understanding of the cost components that make up the life cycle cost is expected to provide the product designers an opportunity to considerably reduce product LCC. In this paper, a methodology for LCC analysis based on reliability and maintainability principles has been applied to three different pumps and the results of analysis have been compared. For analysis purpose, two pumps have been selected from the literature and the data available therein is utilized. The third pump is selected from a well known pump manufacturer from India and the required data is obtained directly from the manufacturer. To model the maintenance and repair cost the concept of expected number of failures in a given time interval has been applied. The maintenance and repair cost is estimated for two different maintenance and repair strategies, the renewal/replacement upon failure strategy and minimal repair upon failure strategy and under the conditions of constant failure rate (exponential distribution) in first case and increasing failure rate (Weibull distribution) in the second case. The results obtained have been presented and compared at the end. The methodology presented in this paper is expected to help the pump designers to estimate and compare the life cycle cost of their different design alternatives.

scholarly journals Life Cycle Cost of Electricity Production: A Comparative Study of Coal-Fired, Biomass, and Wind Power in China

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3463
Author(s):  
Xueliang Yuan ◽  
Leping Chen ◽  
Xuerou Sheng ◽  
Mengyue Liu ◽  
Yue Xu ◽  
...  
Keyword(s):  
Power Generation ◽  
Life Cycle ◽  
Wind Power ◽  
Life Cycle Cost ◽  
Raw Material ◽  
Electricity Production ◽  
Maintenance Cost ◽  
External Cost ◽  
Levelized Cost Of Electricity ◽  
Cost Of Electricity

Economic cost is decisive for the development of different power generation. Life cycle cost (LCC) is a useful tool in calculating the cost at all life stages of electricity generation. This study improves the levelized cost of electricity (LCOE) model as the LCC calculation methods from three aspects, including considering the quantification of external cost, expanding the compositions of internal cost, and discounting power generation. The improved LCOE model is applied to three representative kinds of power generation, namely, coal-fired, biomass, and wind power in China, in the base year 2015. The external cost is quantified based on the ReCiPe model and an economic value conversion factor system. Results show that the internal cost of coal-fired, biomass, and wind power are 0.049, 0.098, and 0.081 USD/kWh, separately. With the quantification of external cost, the LCCs of the three are 0.275, 0.249, and 0.081 USD/kWh, respectively. Sensitivity analysis is conducted on the discount rate and five cost factors, namely, the capital cost, raw material cost, operational and maintenance cost (O&M cost), other annual costs, and external costs. The results provide a quantitative reference for decision makings of electricity production and consumption.

Reliability Analysis of Repairable Systems Subject to System Modifications

1998 ◽  
Author(s):  
Z. H. Jiang ◽  
L. H. Shu ◽  
B. Benhabib
Keyword(s):  
Life Cycle ◽  
Steady State ◽  
Cost Estimation ◽  
Life Cycle Cost ◽  
Repairable Systems ◽  
Environmentally Conscious ◽  
Reliability Indices ◽  
Reliability Models ◽  
System Reconfiguration ◽  
Environmentally Conscious Design

Abstract This paper approaches environmentally conscious design by further developing a reliability model that facilitates design for reuse. Many reliability models are not suitable for describing systems that undergo repairs performed during remanufacture and maintenance because the models do not allow the possibility of system reconfiguration. In this paper, expressions of reliability indices of a model that allows system reconfiguration are developed to enable life-cycle cost estimation for repairable systems. These reliability indices of a population of repairable systems are proven theoretically to reach steady state. The expressions of these indices at steady state are obtained to gain insight into the model behavior, and to facilitate life-cycle cost estimation.

Integrating Reliability Analysis in Life Cycle Cost Estimation of Heat Exchanger and Pump

2014 ◽  
Vol 903 ◽  
pp. 408-413 ◽  
Author(s):  
FRESELAM Mulubrhan ◽  
Ainul Akmar Mokhtar ◽  
Masdi Muhammad
Keyword(s):  
Life Cycle ◽  
Heat Exchanger ◽  
Cost Estimation ◽  
Life Cycle Cost ◽  
Distribution Model ◽  
Maintenance Cost ◽  
Published Data ◽  
Acquisition Costs ◽  
Maintenance Policies ◽  
High Degree

This paper presents a mathematical model to estimate the life cycle cost (LCC) of heat exchanger and pump. Maintenance cost, down time cost and acquisition costs are calculated. The main uncertainty in calculating these costs are prediction of number of failure and cumulative down time. Number of failure is determined using failure and repair time density function. According to the characteristic that the cumulative failure probability observed, a Weibull distribution model is used. The scale and shape parameters of the Weibull are extracted from the published data. The results of the study show that 71.3% loss in the reliability of heat exchanger and 34.2% reliability loss in pump could lead to 66.2 % increment of the total cost. The reliability of the system decreases because of number of failures will increase each year, and this failure leads to unavailability of the system.Therefore in order to achieve higher system effectiveness and reduce the total LCC, the reliability of the systems need to be increased through proper maintenance policies and strategies. The results of the study could assist the managers to make decision with high degree of accuracy.

Performance Evaluation of Seismic Force–Resisting Systems for Low-Rise Steel Buildings in Canada

2015 ◽  
Vol 31 (4) ◽  
pp. 1969-1990 ◽  
Author(s):  
T. Y. Yang ◽  
M. Murphy
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Seismic Damage ◽  
Maintenance Cost ◽  
Life Cycle Costs ◽  
Finite Element Models ◽  
Steel Buildings ◽  
Material Usage ◽  
Seismic Force ◽  
Seismic System

Steel is one of the most popular seismic force–resisting systems (SFRS) in use worldwide. In Canada, several SFRS have been prequalified for use in the national and provincial building codes. The design of each SFRS has been covered comprehensively in literature. However, no guidance has been provided in selecting the optimum system for a project. In this paper, a prototype building located in Vancouver, Canada, was designed nine times to utilize each of the prequalified SFRS. Detailed seismic hazard and finite element models were developed for each system. The performance in terms of initial construction and life-cycle cost was used to rank each SFRS. The result of this analysis shows that the eccentrically braced configuration has the lowest material usage and life cycle maintenance cost; it is therefore the most economic system in this study. The presented methodology is transparent and can be easily adopted by engineers to select the most economic seismic system for projects with different configurations and geometries than those given in this research. Furthermore, this system introduces a metric with which to estimate the life-cycle costs of a structure taking into account seismic damage over the service life.

Life Cycle Cost Management Strategy on Corrosion Deterioration and Fatigue Damage of Steel Girder Bridge

2008 ◽  
Vol 385-387 ◽  
pp. 845-848
Author(s):  
Moe M.S. Cheung ◽  
Kevin K.L. So ◽  
Xue Qing Zhang
Keyword(s):  
Life Cycle ◽  
Fatigue Damage ◽  
Life Cycle Cost ◽  
Management Strategies ◽  
Maintenance Cost ◽  
Steel Girder ◽  
Damage Models ◽  
Failure Cost ◽  
Steel Girder Bridge ◽  
Girder Bridge

This paper proposes a life-cycle cost (LCC) management methodology that integrates corrosion deterioration and fatigue damage mechanisms. This LCC management methodology has four characterized features: (1) corrosion deterioration and fatigue damage models are used to predict the time when the pre-defined limits are reached; (2) the performance of the steel girder is measured by condition state sets in which deflection, moment and shear capacities and fatigue strength limits are considered altogether; (3) the cost-effectiveness of management strategies are measured by the performance improvement per unit of money spent; and (4) the LCC model includes initial design/construction cost, inspection cost, maintenance cost, repair/rehabilitation cost and failure cost. A steel girder bridge is used as an example to demonstrate the application of the proposed LCC management methodology.

Innovative Approach for Use of Hydrofoils on Ultralight Seaplane

2020 ◽  
Author(s):  
Antonio Maglione ◽  
Ubaldo Cella ◽  
Marco E. Biancolini ◽  
Leonardo Lecce
Keyword(s):  
Life Cycle ◽  
Power Plant ◽  
Life Cycle Cost ◽  
Water Surface ◽  
Maintenance Cost ◽  
Wave Forces ◽  
Water Spray ◽  
Sea State ◽  
Important Benefit ◽  
Plant Maintenance

Retractable hydrofoils may enhance performances of seaplane during take-off and landing runs by lowering the speed when the hull is leaving or touching water surface. Hydrofoils are designed to complement airlift with additional hydrodynamic lift elevating the hull above the water at a speed lower than take-off speed; this minimizes slamming phenomenon on the hull, improving seakeeping capability of the seaplane, since water impacts are minimized compared to conventional configuration and, as a consequence, forces and accelerations on airframe, crew and passengers are reduced. This is of foremost importance on ultralight seaplanes, where wave forces acting on the relatively small aircraft mass provide high accelerations and significant roll, pitch and yaw forces that are higher on light aircraft compared to heavy seaplanes. As matter of facts, clear advantage of this configuration is the increase of sea state when a light seaplane can safely fly, providing additional useful days along the year. Important benefit is the improvement of seaplane performances during take-off and landing, reducing duration of the most critical flight phases, increasing overall safety and reducing pilot workload. Further benefits are envisioned, with optimization of wing, empennage and fuselage to minimize aero-drag and, as snow-ball effect, mission fuel consumption and energy power requirements. Life-cycle cost receives benefits too, since less water spray is ingested by engine and less water droplets impinge on fast revolving propeller, thus reducing expensive power plant maintenance cost over the entire service life.

scholarly journals An Automated Procedure for Assessing Local Reliability Index and Life-Cycle Cost of Alternative Girder Bridge Design Solutions

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Ilaria Venanzi ◽  
Riccardo Castellani ◽  
Laura Ierimonti ◽  
Filippo Ubertini
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Design Solution ◽  
Bridge Design ◽  
Limit States ◽  
Technical Standards ◽  
Local Character ◽  
Repair Costs ◽  
Design Solutions ◽  
Girder Bridge

Stakeholders of civil infrastructures have to usually choose among several design alternatives in order to select a final design representing the best trade-off between safety and economy, in a life-cycle perspective. In this framework, the paper proposes an automated procedure for the estimation of life-cycle repair costs of different bridge design solutions. The procedure provides the levels of safety locally guaranteed by the selected design solution and the related total life-cycle cost. The method is based on the finite element modeling of the bridge and uses design traffic models as suggested by international technical standards. Both the global behavior and the transversal cross section of the bridge are analyzed in order to provide local reliability indexes. Several parameters involved in the design, such as geometry and loads and materials’ characteristics, are considered as uncertain. Degradation models are adopted for steel carpentry and rebars. The application of the procedure to a road bridge case study shows its potential in providing local safety levels for different limit states over the entire lifetime of the bridge and the life-cycle cost of the infrastructure, highlighting the importance of the local character of the life-cycle cost analysis.

Sign in / Sign up

Export Citation Format

Share Document